U.S. patent number 8,163,819 [Application Number 12/767,857] was granted by the patent office on 2012-04-24 for adhesive compositions, micro-fluid ejection devices and methods for attaching micro-fluid ejection heads.
This patent grant is currently assigned to Lexmark International, Inc.. Invention is credited to David Christopher Graham, Gary Anthony Holt, Jr., Jonathan Harold Laurer, Johnny Dale Massie, II, Melissa Marie Waldeck, Sean Terrence Weaver, Rich Wells.
United States Patent |
8,163,819 |
Graham , et al. |
April 24, 2012 |
Adhesive compositions, micro-fluid ejection devices and methods for
attaching micro-fluid ejection heads
Abstract
Adhesive compositions, micro-fluid ejection devices, and methods
for attaching micro-fluid ejection heads to devices. One such
adhesive composition is provided for use in attaching a micro-fluid
ejection head to a device, such as to reduce chip bowing and/or to
decrease chip fragility upon curing of the adhesive. Such an
exemplary composition may include one having from about 50.0 to
about 95.0 percent by weight of at least one cross-linkable resin
selected from the group consisting of epoxy resins, siloxane
resins, urethane resins, and functionalized olefin resins; from
about 0.1 to about 25.0 percent by weight of at least one thermal
curative agent; and from about 0.0 to about 30.0 percent by weight
filler, and exhibit a relatively low shear modulus upon curing
(e.g., less than about 10.0 MPa at 25.degree. C.).
Inventors: |
Graham; David Christopher
(Lexington, KY), Holt, Jr.; Gary Anthony (Lexington, KY),
Laurer; Jonathan Harold (Boone, NC), Massie, II; Johnny
Dale (Lexington, KY), Waldeck; Melissa Marie (Lexington,
KY), Weaver; Sean Terrence (Union, KY), Wells; Rich
(Westerville, OH) |
Assignee: |
Lexmark International, Inc.
(Lexington, KY)
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Family
ID: |
38574771 |
Appl.
No.: |
12/767,857 |
Filed: |
April 27, 2010 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20100210759 A1 |
Aug 19, 2010 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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11382876 |
May 11, 2006 |
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60743920 |
Mar 29, 2006 |
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Current U.S.
Class: |
523/461;
523/466 |
Current CPC
Class: |
B41J
2/1601 (20130101); B41J 2/14024 (20130101); B41J
2/1623 (20130101); B41J 2/1408 (20130101) |
Current International
Class: |
C08L
63/00 (20060101); C09J 163/00 (20060101) |
Field of
Search: |
;523/457,458,461,466
;525/523,524 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Feely; Michael J
Parent Case Text
RELATED APPLICATIONS
This application is a continuation application of parent
application Ser. No. 11/382,876, filed May 11, 2006 (now
abandoned), entitled "Adhesive Compositions, Micro-Fluid Ejection
Devices, and Methods for Attaching Micro-Fluid Ejection Heads"
which claims priority to provisional application Ser. No.
60/743,920, filed Mar. 29, 2006.
Claims
What is claimed is:
1. A thermally curable adhesive composition for attaching a
micro-fluid ejection head to a device, the adhesive composition
comprising: from 55.0 to 88.0 percent by weight, based on the
overall adhesive composition, of a flexible epoxy resin; from
greater than 0 to 3.5 percent by weight, based on the overall
adhesive composition, of an amine adduct; from 7.4 to 11.0 percent
by weight, based on the overall adhesive composition, of an
imidazole catalyst thermal curative agent; and from 0.6 to 1.0
percent by weight, based on the overall adhesive composition, of an
epoxy silane coupling agent, wherein the adhesive composition has
shear modulus of less than about 10 MPa at 25.degree. C. and glass
transition temperature of less than about 65.degree. C.
2. The adhesive composition of claim 1, further comprising from
greater than 0 to 3.5 percent by weight, based on the overall
adhesive composition, of a fumed silica.
Description
TECHNICAL FIELD
The disclosure relates to adhesive compositions, and in one
particular embodiment, to flexible compounds that can be cured for
use as adhesives in micro-fluid ejection devices.
BACKGROUND AND SUMMARY
Micro-fluid ejection heads are useful for ejecting a variety of
fluids including inks, cooling fluids, pharmaceuticals, lubricants
and the like. A widely used micro-fluid ejection head is an inkjet
print head used in an ink jet printer. Ink jet printers continue to
be improved as the technology for making their micro-fluid ejection
heads continues to advance.
In the production of conventional thermal ink jet print cartridges
for use in ink jet printers, one or more micro-fluid ejection heads
are typically bonded to one or more chip pockets of an ejection
device structure. A micro-fluid ejection head typically includes a
fluid-receiving opening and fluid supply channels through which
fluid travels to a plurality of bubble chambers. Each bubble
chamber includes an actuator such as a resistor which, when
addressed with an energy pulse, momentarily vaporizes the fluid and
forms a bubble which expels a fluid droplet. The micro-fluid
ejection head typically comprises an ejector chip and a nozzle
plate having a plurality of discharge orifices formed therein.
A container, which may be integral with, detachable from or
remotely connected to (such as by tubing) the ejection device
structure, serves as a reservoir for the fluid and includes a fluid
supply opening that communicates with a fluid-receiving opening of
a micro-fluid ejection head for supplying ink to the bubble
chambers in the micro-fluid ejection head.
During assembly of the micro-fluid ejection head to the ejection
device structure, an adhesive is used to bond the ejection head to
the ejection device structure. The adhesive "fixes" the micro-fluid
ejection head to the ejection device structure such that its
location relative to the ejection device structure is substantially
immovable and does not shift during processing or use of the
ejection head. The bonding and fixing step is often referred to as
a "die attach step." Further, the adhesive may provide additional
functions such as serving as a fluid gasket against leakage of
fluid and as corrosion protection for conductive tracing. The
latter function for the adhesive is referred to as part of the
adhesive's encapsulating function, thereby further defining the
adhesive as an "encapsulant" to protect electrical components of or
used with the micro-fluid ejection head, such as a flexible circuit
(e.g., a TAB circuit) attached to the micro-fluid ejection
head.
However, the micro-fluid ejection head and the ejection device
structure typically have dissimilar coefficients of thermal
expansion. For example, micro-fluid ejection heads may have silicon
or ceramic substrates that are bonded to an ejection device
structure that may be a polymeric material such as a modified
phenylene oxide. Thus, the adhesive must often accommodate both
dissimilar expansions and contractions of the micro-fluid ejection
head and the ejection device structure, and be resistant to attack
by the ejected fluid.
Conventional adhesive materials tend to be non-flexible and brittle
after curing due to high temperatures required for curing and
relatively high shear modulus of the adhesive materials upon
curing. Such properties may cause the adhesive materials to chip or
crack. It may also cause the components (e.g., micro-fluid ejection
head and/or ejection device structure) to bow, chip, crack, or
otherwise separate from one another, or to be less resilient to
external forces (e.g., chips may be more prone to crack when
dropped). For example, during a conventional thermal curing
process, the ejection device structure typically expands before a
conventional die bond adhesive material is fully cured. The diebond
material thus moves with the expanding device structure, wherein
the diebond material cures with the device structure in an expanded
state. Upon cooling the device structure, the device structure
contracts and, with a rigid, cured diebond material, induces high
stress onto the ejection head to cause the aforementioned bowing,
chipping, cracking, separating, etc. Among other problems, such
events can result in fluid leakage and poor adhesion as well as
malfunctioning of the micro-fluid ejection heads, such as
misdirected nozzles. Moreover, attempts to make adhesive materials
more flexible after curing often lead to adhesive materials that
are less resistant to chemical degradation by the fluids being
ejected.
Accordingly, a need exists for, amongst other things, a flexible
adhesive composition that is curable at relatively low temperatures
and that is suitable for use in assembling micro-fluid ejection
head components, and particularly, for attaching micro-fluid
ejection heads to ejection device structures.
With regard to the foregoing and other object and advantages,
various embodiments of the disclosure provide a thermally curable
adhesive composition for attaching a micro-fluid ejection head to a
device wherein the adhesive has a relatively low shear modulus upon
curing. Various exemplary embodiments also provide a micro-fluid
ejection head having an ejector chip and a thermally curable
adhesive attached thereto, the adhesive having a shear modulus of
less than about 10 MPa at 25.degree. C., wherein "MPa" stands for
"MegaPascals" (i.e., 1.0.times.10.sup.6 Pascals).
Additionally, embodiments provide a micro-fluid ejection device
having an ejector chip and a thermally curable adhesive attached
thereto, the adhesive having a glass transition temperature of less
than about 65.degree. C. Various other embodiments provide a method
for attaching a micro-fluid ejection head to a device. One such
method includes attaching the head to a device with a thermally
curable adhesive with a relatively low shear modulus dispensed
between the head and the device, and curing the adhesive
composition to provide the micro-fluid ejection device.
Advantages of the exemplary embodiments may include, but are not
limited to, a reduction in ejector chip substrate bow, an increase
in ejector head durability, increased planarity of the ejector
head, and the like. Other advantages might include the provision of
adhesives having improved mechanical, adhesive, and ink resistive
properties. Reduced stresses may be present in the ejector head
substrates due to the presence of improved adhesives according to
the disclosed embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
Further features and advantages of the disclosed embodiments may
become apparent by reference to the detailed description when
considered in conjunction with the figures, which are not to scale,
wherein like reference numbers indicate like elements through the
several views, and wherein:
FIG. 1 is a perspective view of a micro-fluid ejection device
according to an exemplary embodiment of the disclosure;
FIG. 2, is a perspective view, not to scale, of an ink jet printer
capable of controlling a micro-fluid ejection device according to
the disclosure;
FIG. 3 is a cross-sectional view, not to scale, of a portion of a
micro-fluid ejection device according to an embodiment of the
disclosure;
FIG. 4A is a cross-sectional view, not to scale, of a micro-fluid
ejection device incorporating one or more prior art adhesive
compositions; and
FIG. 4B is a cross-sectional cutaway side view, not to scale, of a
portion of a micro-fluid ejection device according to an embodiment
of the disclosure.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
In general, the disclosure is directed to describing improved
compositions, structures, and methods related to thermally curable
adhesives used to assemble component parts of micro-fluid ejection
devices. More specifically, the improved adhesive compositions
discussed herein might be used to, for example, reduce residual
stresses that may result from heat-treating micro-fluid ejection
heads to cure the adhesives.
In order to more fully disclose various embodiments of the
invention, attention is directed to the following description of a
representative micro-fluid ejection device incorporating the
improved thermally curable adhesive described herein. With
reference to FIG. 1, there is shown, in perspective view, a
micro-fluid ejection device 10 including one or more micro-fluid
ejection heads 12 attached to a head portion 14 of the device 10. A
fluid reservoir 16 containing one or more fluids is fixedly (or
removably) attached to the head portion 14 for feeding fluid to the
one or more micro-fluid ejection heads 12 for ejection of fluid
toward a media or substrate from nozzles 18 on a nozzle plate 20.
Although FIG. 1 illustrates the fluid reservoir being directly
attached to a head portion 14, other embodiments might attach a
fluid reservoir indirectly to a head portion, such as by tubing,
for example. Each reservoir 16 may contain a single fluid, such as
a black, cyan, magenta or yellow ink or may contain multiple
fluids. In the illustration shown in FIG. 1, the device 10 has a
single micro-fluid ejection head 12 for ejecting a single fluid.
However, the device 10 may contain two or more ejection heads for
ejecting two or more fluids, or a single ejection head 12 may eject
multiple fluids, or other variations on the same.
In order to control the ejection of fluid from the nozzles 18, each
of the micro-fluid ejection heads 12 is usually electrically
connected to a controller in an ejection control device, such as,
for example, a printer 21 (FIG. 2), to which the device 10 is
attached. In the illustrated embodiment, connections between the
controller and the device 10 are provided by contact pads 22 which
are disposed on a first portion 24 of a flexible circuit 26. An
exemplary flexible circuit 26 is formed from a resilient polymeric
film, such as a polyimide film, which has conductive traces 28
thereon for conducting electrical signals from a source to the
ejection head 12 connected to the traces 28 of the flexible circuit
26. A second portion 30 of the flexible circuit 26 is typically
disposed on an operative side 32 of the head portion 14. The
reverse side of the flexible circuit 26 typically contains the
traces 28 which provide electrical continuity between the contact
pads 22 and the micro-fluid ejection heads 12 for controlling the
ejection of fluid from the micro-fluid ejection heads 12. TAB bond
or wire bond connections, for example, are made between the traces
28 and each individual micro-fluid ejection head 12 as described in
more detail below.
Exemplary connections between a flexible circuit and a micro-fluid
ejection head are shown in detail by reference to FIG. 3. As
described above, flexible circuits 26 contain traces 28 which are
electrically connected to a substrate 34. The substrate 34 may be
part of an ejector chip having resistors and/or other actuators,
such as piezoelectric devices or MEMs devices for inducing ejection
of fluid through nozzles 18 of a nozzle plate 20 toward a print
media. Connection pads 36 on the flexible circuits 26 are
operatively connected to bond pads 38 on the substrate 34, such as
by TAB bonding techniques or by use of wires 40 using a wire
bonding procedure through windows 42 and/or 44 in the circuit 26
and/or nozzle plate 20.
As shown in FIG. 3, the substrate 34 is attached to the head
portion 14, such as in a chip pocket 46. Prior to attaching the
substrate 34 to the head portion 14, a nozzle plate 20 may be
adhesively attached to the ejector chip using adhesive 48 (in
another embodiment, a nozzle plate may be attached to the ejector
chip by forming the nozzle plate on the substrate using
photoimageable techniques). The assembly provided by the nozzle
plate 20 attached to the substrate 34 is referred to herein as the
substrate/nozzle plate assembly 20/34 (FIG. 3). In some
embodiments, the assembly 20/34 encompasses the micro-fluid
ejection head itself.
The adhesive 48 may be a heat curable adhesive such a B-stageable
thermal cure resin, including, but not limited to phenolic resins,
resorcinol resins, epoxy resins, ethylene-urea resins, furane
resins, polyurethane resins and silicone resins. The adhesive 48
may be cured before attaching the substrate 34 to the head portion
14 and, in an exemplary embodiment, the adhesive 48 has a thickness
ranging from about 1 to about 25 microns.
After bonding the nozzle plate 20 and substrate 34 together, the
substrate/nozzle plate assembly 20/34 may be attached to the head
portion 14 in chip pocket 46 using a die bond adhesive 50. In
various embodiments of the disclosure, the die bond adhesive 50
used to connect the substrate/nozzle plate assembly 20/34 to the
head portion 14 includes one or more adhesive components that make
up a composition having a relatively low shear modulus.
"Shear modulus" involves the relation of stress to strain according
to Hooke's Law as shown in Equation (1) as follows:
(stress)=.mu.(strain) (1) In Equation (1), ".mu." represents a
quantity often referred to as rigidity. When the relationship
illustrated by Equation (1) is applied to a force "F" across a
given area "A," Equation (1) may be more specifically represented
by Equation (2) as follows: F/A=.mu.(.DELTA.L/L) (2) In Equation
(2) above, the variable "L" represents original length of an object
before said object was acted upon by force F. ".DELTA.L" represents
the change in length occurring after force "F" has acted upon the
object. Therefore, the rigidity (".mu.") of the object is a
proportionality constant relating the pressure applied to an object
with the ratio between the object change in length with the objects
original length.
When Equation (2) and a given rigidity value ".mu." are used to
determine elastic properties of an object, Equation (3), shown
below, is used to derive a shear modulus value from the rigidity
".mu." value determined in Equation (2). Equation (3) is shown
below as follows: .mu.=E/2(L+v) (3) In Equation (3) above, shear
modulus is the proportional relationship between rigidity ".mu."
and the right hand side of the equation, including the Poisson
ratio "v" and Young's modulus "E."
Applying Hooke's Law and elasticity theory to physical properties
of micro-fluid ejection heads, reliable data may be established to
correlate the elastic properties of adhesives with the effect of
said adhesives on one or more surfaces of a micro-fluid ejection
head. Shear modulus values are dependent on temperature, therefore,
a given shear modulus value for a given adhesive will be given in
pressure units at a specific temperature. Various embodiments of
the disclosure include compositions with shear modulus values of
less than 10 MPa at 25.degree. C. as determine by a rheometer from
TA Instruments of New Castle, Del. under the trade name ARES in a
dynamic parallel plate configuration with a frequency of 1.0
rad/sec and a strain of 0.3% after the material is cured. In
certain exemplary embodiments, one or more of the claimed
compositions have shear modulus values of less than about 1.0 MPa
at 25.degree. C.
With reference now to FIG. 4A, a cross-sectional view of a
non-planar micro-fluid ejection head 12 (e.g., substrate/nozzle
plate assembly 20/34) is illustrated. The substrate/nozzle plate
assembly 20/34 is attached to a head portion 14 in a chip pocket
46. In the prior art ejection head 12, the substrate/nozzle plate
assembly 20/34 was attached to the chip pocket 46 using a prior art
die attach adhesive 58 having a shear modulus of substantially more
than 10 MPa at 25.degree. C. The non-planar characteristic of
micro-fluid ejection head 12 is caused at least in part by high
temperature curing of the die attach adhesive 58.
The example shown in FIG. 4A is provided to illustrate certain
undesirable effects of high temperature curing including non-planar
micro-fluid ejection head surfaces causing undesirable effects such
as "chip bowing," adhesive layer cracking, and increased overall
fragility of the micro-fluid ejection head 12 and substrate/nozzle
plate assembly 20/34. Chip bowing typically results from the
substrate/nozzle plate assembly 20/34 and the head portion 14
having dissimilar coefficients of thermal expansion, since the
surface of the substrate/nozzle plate assembly 20/34 bonded to the
head portion 14 most commonly is silicon or ceramic and the portion
14 is, for example, typically a polymeric material such as a
modified phenylene oxide. Thus, the adhesive 58 should be flexible
enough to accommodate both the dissimilar expansions and
contractions of the substrate chip/nozzle plate assembly 20/34 and
the head portion 14. Chip bowing may result in nozzles being
misaligned or aligned at an undesired angle (often called
"planarity" of nozzles), which may also diminish the quality of
fluid ejected from the nozzles.
Chip fragility is believed to increase in severity because the
adhesive layer reaches its glass transition temperature (T.sub.g)
before the substrate/nozzle plate assembly 20/34 and head portion
14 have finished cooling and contracting relative to one another
after the curing of the adhesive layer 58, imparting stress onto
the substrate/nozzle plate assembly. Accordingly, in an exemplary
embodiment of the invention, an adhesive is used that has glass
transition temperature below the temperature to which the head
portion 14 is cooled. For example, an adhesive with a glass
transition temperature of less than about 65.degree. C., such as
one having a glass transition temperature of less than about
50.degree. C. or less than about 25.degree. C. might be used in an
exemplary embodiment.
The glass transition temperature of a material with elastic
properties is the temperature at which the material transitions to
more brittle physical properties or more elastic physical
properties, depending on whether the temperature is decreasing or
increasing, respectively. After curing, as the adhesive layer 58
cools below its glass transition temperature, the adhesive 58
becomes significantly more brittle than before reaching its glass
transition temperature. If the adhesive 58 is stretched or
compressed at a temperature below its glass transition temperature,
the adhesive may crack or buckle. Therefore, using adhesives with
lower glass transition temperatures will decrease the chances of
adhesive cracking or buckling. Similarly, considering that shear
modulus values directly relate to how brittle an adhesive will be
at a given temperature, adhesives having lower shear modulus values
are more flexible at lower temperatures, thereby decreasing the
likelihood of adhesive cracking or buckling. Adhesive layer
cracking may result in a compromised fluid seal, whereby
micro-fluid ejection fluid leaks from the substrate/nozzle plate
assembly 20/34 might cause undesirable deposits of fluid, and/or
corrosion of electrical components.
High curing temperatures may also cause increased fragility.
Adhesives having lower shear modulus values and lower glass
transition temperatures may be cured with lower temperatures
thereby, decreasing the chances for micro-fluid ejection head
fragility. Increased fragility of micro-fluid ejection heads
increases the chances for micro-fluid ejection products becoming
unfit for use due to shattering of micro-fluid ejections heads and
other parts of the micro-fluid ejection device.
In contrast to FIG. 4A, the head portion 14 shown in FIG. 4B
illustrates a micro-fluid ejection head 12 comprising a
substrate/nozzle plate assembly 20/34 that is attached to the chip
pocket 46 using die attach adhesive 50 made of one or more of the
compositions described herein. Using compositions such as that
described below may result in decreased chip bowing, decreased
micro-fluid ejection head cracking, and/or decreased fragility of
micro-fluid ejection heads. Such improved characteristics may be
possible by the use of a die attach adhesive having a relatively
low shear modulus. For the purposes of certain embodiments in this
disclosure, "relatively low shear modulus" is defined as a shear
modulus at least lower than about 10 MPa at 25.degree. C.
"Relatively low shear modulus" may, however, be defined as a shear
modulus lower than about 1.0 MPa at 25.degree. C. for certain
exemplary embodiments disclosed herein.
In an exemplary embodiment, die attach adhesive 50 is a composition
including (1) from about 50.0 to about 95.0 percent by weight of at
least one cross-linkable resin selected from the group of epoxy
resins, siloxane resins, urethane resins, and functionalized olefin
resins; (2) from about 0.1 to about 25.0 percent by weight of at
least one thermal curative agent selected from the group of
imidazoles, amines, peroxides, organic accelerators, and sulfur;
and (3) from about 0.0 to about 30.0 percent by weight filler,
wherein the composition exhibits a relatively low shear modulus
upon curing. In some variations of these exemplary embodiments, the
adhesive 50 may include from about 0.0 to about 10.0 percent by
weight silane coupling agent. In the embodiments described above,
the filler may include from about 0.0 to about 30.0 percent by
weight titanium dioxide, and from about 0.0 to about 30.0 percent
by weight fumed silica or another filler component such as clay or
functionalized clay, silica, talc, carbon black, carbon fibers.
More specific exemplary embodiments of the composition of adhesive
50 are listed in Tables 1 through Table 7 below.
TABLE-US-00001 TABLE 1 (Composition 1) Concentration (percent
Material by weight) Trade name Supplier Flexible epoxy resin 37.8
GE-35 CVC Aliphatic flexible 37.8 Epalloy 3-23 CVC epoxy resin
Bisphenol M 8.4 Bisphenol M Aldrich Imidazole catalyst 9.5
Curezol-17-Z Air Products Epoxy silane 0.2 A-187 GE Silicones
Titanium dioxide 4.2 Ti-Pure R-900 DuPont Fumed Silica 2.1 TS-720
Cabot
As shown above, composition 1 includes from about 25.0 to about
50.0 percent by weight multi-functional epoxy resin; from about
25.0 to about 50.0 percent by weight aliphatic di-functional epoxy
resin; and from about 0.1 to about 15.0 percent by weight phenolic
cross-linking agent. The composition also includes from about 0.1
to about 20.0 percent by weight of an imidazole catalyst and from
about 0.0 to about 30.0 weight percent fillers. As shown in Table
8, Composition 1 has a relatively low shear modulus value of about
0.225 MPa at 25.degree. C. and a low glass transition temperature
of about 10.5.degree. C.
There are a number of epoxy resins, curing agents, and fillers
available for application with various embodiments of the
invention. In the first composition illustrated in Table 1, an
exemplary multi-functional epoxy resin is available from CVC
Specialty Chemicals, Inc. under the trade name ERISYS GE-35. An
exemplary aliphatic di-functional epoxy resin is available from CVC
Specialty Chemicals, Inc. under the trade name EPALLOY 3-23. A
suitable phenolic cross-linking agent is available from Sigma
Aldrich Company under the trade designation Bisphenol M. A useful
curing agent is available from Air Products and Chemicals, Inc.
under the trade name CUREZOL C17Z. A suitable epoxy silane coupling
agent is available from GE Advanced Materials, Silicones of Wilton,
Conn. under the trade name SILQUEST A-187 SILANE. Suitable fillers
such as titanium dioxide, and fumed silica are available from a
number of different suppliers. For example, titanium dioxide is
available from DuPont Titanium Technologies under the trade name
TI-PURE R-900 and fumed silica is available from Cabot Corporation
of Boston, Mass. under the trade name CAB-O-SILTS-720.
TABLE-US-00002 TABLE 2 (Composition 2) Concentration (percent
Material by weight) Trade name Supplier Diphenyl siloxane 79.5
PMS-E15 Gelest Tetraethylene- 7.7 TEPA Air Products pentamine Epoxy
Silane 0.9 A-187 GE Silicones Titanium dioxide 4.0 Ti-Pure R-900
Dupont Fumed Silica 7.9 TS-720 Cabot
In Table 2, composition 2, includes from about 50.0 to about 95.0
percent by weight diphenyl siloxane resin, from about 0.1 to about
20.0 percent by weight of tetraethylenepentamine, and from about
0.0 to about 10.0 percent by weight epoxy silane. The fillers
include from about 0.0 to about 30.0 percent by weight titanium
dioxide; and from about 0.0 to about 30.0 percent by weight fumed
silica. As shown in Table 8, Composition 2 has a relatively low
shear modulus value of about 1.98 MPa at 25.degree. C. and a low
glass transition temperature of about -11.2.degree. C.
In accordance with the foregoing composition, a suitable diphenyl
siloxane resin is available from Gelest, Inc. of Morrisville, Pa.
under the trade name PMS E-15. A useful tetraethylenepentamine
curing agent for this composition is available from Air Products or
Sigma Aldrich Company under the trade designation TEPA
(Tetraethylenepentamine).
TABLE-US-00003 TABLE 3 (Composition 3) Concentration (percent
Material by weight) Trade name Supplier Flexible epoxy resin 19.9
GE-35 CVC Epoxy siloxane 19.9 SIB1115.0 Gelest Carboxyl-terminated
39.7 2000X162 Noveon butadiene Amine adduct 10.7 Ancamine 2337 Air
Products Epoxy Silane 0.2 A-187 GE Silicones Titanium dioxide 4.0
Ti-Pure R-900 Dupont Fumed Silica 5.6 TS-720 Cabot
Table 3 illustrates yet another exemplary adhesive composition.
Composition 3 includes from about 0.0 to about 50.0 percent by
weight multi-functional epoxy resin; from about 0.0 to about 50.0
percent by weight epoxy siloxane resin; from about 0.0 to about
90.0 percent by weight carboxyl-terminated butadiene; and from
about 0.1 to about 20.0 percent by weight of an amine adduct
thermal curative agent. This embodiment also includes from about
0.0 to about 15.0 percent by weight epoxy silane, from about 0.0 to
about 30.0 percent by weight titanium dioxide, and from about 0.0
to about 30.0 percent by weight fumed silica. As shown in Table 8,
Composition 3 has a substantially low shear modulus value of about
0.175 MPa at 25.degree. C. and a low glass transition temperature
of about -6.7.degree. C.
In accordance with the foregoing composition, the epoxy siloxane
that may be used is available from Gelest, Inc. is under the trade
designation SIB1115.0. The carboxyl-terminated butadiene that may
be used is available from Noveon Specialty Chemicals of Cleveland,
Ohio under the trade name HYCAR CTB 2000.times.162. A suitable
curing agent in the form of an amine adduct is available from Air
Products and Chemicals, Inc. under the trade name ANCAMINE
2337S.
TABLE-US-00004 TABLE 4 (Composition 4) Concentration (percent
Material by weight) Trade name Supplier Epoxidized 36.2 Poly BD
600E Sartomer butadiene resin Anhydride 50.7 130-MA-8 Sartomer
functional butadiene Anhydride 6.1 MHHPA Miller-Stephenson cross
linker Azine imidazole 2.3 2MZ-Azine Air Products Epoxy Silane 0.4
A-187 GE Silicones Titanium dioxide 2.0 Ti-Pure R-900 DuPont Fumed
Silica 2.3 TS-720 Cabot
As provided in Table 4, Composition 4 includes from about 0.0 to
about 50.0 percent by weight epoxidized butadiene resin; from about
0.0 to about 75.0 percent by weight anhydride functional butadiene;
from about 0.1 to about 20.0 percent by weight anhydride
cross-linking agent; and from about 0.1 to about 20.0 percent by
weight of an azine imidazole thermal curative agent. From about 0.0
to about 15.0 percent by weight epoxy silane; from about 0.0 to
about 30.0 percent by weight titanium dioxide; and from about 0.0
to about 30.0 percent by weight fumed silica are also included in
the composition. As shown in Table 8, Composition 4 has a
considerably lower shear modulus value of about 0.151 MPa at
25.degree. C. and a considerably lower glass transition temperature
of about -30.degree. C.
For composition 4, a suitable epoxidized butadiene resin is
available from Sartomer Company, Inc. of Exton, Pa. under the trade
name POLY BD 600E. A suitable anhydride functional butadiene resin
that may be used is available from Sartomer Company, Inc. of Exton,
Pa. under the trade name RICON 130MA8. The cross-linking agent that
may be used is available from Miller-Stephenson Chemical Company,
Inc. under the trade designation Anhydride MHHPA. A suitable curing
agent is an azine imidazole that is available from Air Products and
Chemicals, Inc. under the trade name CUREZOL.RTM. 2MZ Azine.
TABLE-US-00005 TABLE 5 (Composition 5) Concentration (percent
Material by weight) Trade name Supplier Methacrylated 86.0 Riacryl
3100 Sartomer butadiene resin Peroxide catalyst 2.8 Luperox LP
Aldrich Epoxy Silane 0.9 A-187 GE Silicones Titanium dioxide 4.3
Ti-Pure R-900 Dupont Fumed Silica 6.0 TS-720 Cabot
As provided in Table 5, Composition 5 includes from about 50.0 to
about 95.0 percent by weight methacrylated butadiene resin, and
from about 0.1 to about 30.0 percent by weight of peroxide catalyst
thermal curative agent. A suitable methacrylated butadiene resin is
available from Sartomer Company, Inc. of Exton, Pa. under the trade
name RICACRYL 3100. The curing agent is suitably a peroxide
catalyst available from Sigma Aldrich Company under the trade name
LUPEROX LP. As shown in Table 8, Composition 5 has a low shear
modulus value of about 0.74 MPa at 25.degree. C. and a considerably
lower glass transition temperature of less than -60.degree. C.
TABLE-US-00006 TABLE 6 (Composition 6) Concentration (percent
Material by weight) Trade name Supplier Flexible 73.6-88.0 EXA-4850
Dainippon Ink epoxy resin Bisphenol M 0-8.4 Bisphenol M Aldrich
Imidazole 9.2-11.0 CUREZOL-17-Z Air Products catalyst Epoxy Silane
0.8-1.0 A-187 GE Silicones Amine adduct 0-4.1 ANCAMINE 2337 Air
Products Fumed Silica 0-4.1 TS-720 Cabot
As provided in Table 6, Composition 6 includes from about 50.0 to
about 95.0 percent by weight flexible epoxy resin, from about 0.0
to about 30 percent by weight bisphenol-M, and from about 0.1 to
about 20.0 percent by weight of imidazole catalyst thermal curative
agent. A suitable flexible epoxy resin is available from Dainippon
Ink and Chemicals, Inc. of Tokyo, Japan under the trade name
EPICLON EXA-4850. As shown in Table 8, Composition 6 has a low
shear modulus value ranging from about 1.75 to about 4.4 MPa at
25.degree. C. and a glass transition temperature ranging from about
20 to about 31.degree. C.
TABLE-US-00007 TABLE 7 (Composition 7) Concentration (percent
Material by weight) Trade name Supplier Flexible 55.0-88.0 EXA-4850
Dainippon Ink epoxy resin Bisphenol-F 0-27.0 830-LVP Dainippon Ink
Imidazole 7.4-11.0 CUREZOL-17-Z Air Products catalyst Epoxy Silane
0.6-1.0 A-187 GE Silicones Amine adduct 0-3.5 ANCAMINE 2337 Air
Products Fumed Silica 0-3.5 TS-720 Cabot
As provided in Table 7, Composition 7 includes from about 50.0 to
about 95.0 percent by weight flexible epoxy resin, from about 0 to
about 50 percent by weight bisphenol-F, from about 0.1 to about
20.0 percent by weight of imidazole catalyst thermal curative
agent, from about 0.1 to about 20 percent by weight epoxy silane
coupling agent, from about 0 to about 20 percent by weight of amine
adduct, and from about 0 to about 30 percent by weight fumed
silica. As shown in Table 8, Composition 7 has a low shear modulus
value ranging from about 3.9 to about 8.7 MPa at 25.degree. C. and
a glass transition temperature ranging from about 27 to about
60.degree. C.
A comparison of the shear modulus and glass transition temperature
properties of the Compositions 1-7 compared to a conventional die
bond adhesive available from Emerson & Cuming of Monroe
Township, N.J. under the trade name ECCOBOND 3193-17 are provided
in Table 8.
TABLE-US-00008 TABLE 8 Shear Modulus (MPa) Sample (25.degree. C.)
Tg (.degree. C.) Eccobond 3193-17 15.4 92.3 Composition 1 0.225
10.5 Composition 2 1.98 -11.2 Composition 3 0.175 -6.7 Composition
4 0.151 -30 Composition 5 0.74 <-60 Composition 6 1.75-4.4 20-31
Composition 7 3.9-8.72 27.7-60
As illustrated in Table 8, the ECCOBOND 3193-17 adhesive has a
relatively high shear modulus value of 15.4 MPa at 25.degree. C. as
compared to the shear modulus values of the Compositions 1-7 which
are all less than 10 MPa at 25.degree. C. Similarly, the ECCOBOND
3193-17 has a relatively high glass transition temperature of
92.3.degree. C. compared to the much lower values of the
compositions 1-7 which are all less than 65.degree. C. In other
words, ECCOBOND 3193-17 becomes significantly more rigid when it
cools to about 92.degree. C., whereas Compositions 1-7 do not
become significantly more rigid until cooling to at least about
65.degree. C.
Various embodiments of the invention are also directed to a
micro-fluid ejection device including a substrate/nozzle plate
assembly and a thermally curable adhesive attached thereto, the
adhesive having a shear modulus of less than about 10.0 MPa at
25.degree. C. In one particular embodiment, shown in FIG. 4B, a
substrate/nozzle plate assembly 20/34 is attached to head portion
14 by a die attach adhesive 50 made according to Composition 1
above. In a related embodiment, a substrate chip/nozzle plate
assembly 20/34 is attached to a head portion by a die attach
adhesive made according to Composition 2 above. In yet other
embodiments, micro-fluid ejection heads are attached to head
portions by die attach adhesives made according to Compositions 3,
4 and 5 above having a relatively low shear modulus values at
25.degree. C. and having glass transition temperatures of less than
about 65.degree. C.
It is contemplated, and will be apparent to those skilled in the
art from the preceding description and the accompanying drawings
that modifications and/or changes may be made to the embodiments of
the disclosure. Accordingly, it is expressly intended that the
foregoing description and the accompanying drawings are
illustrative of exemplary embodiments only, not limiting thereto,
and that the true spirit and scope of the present disclosure be
determined by reference to the appended claims.
* * * * *